Multi-Photon Entanglement

Interesting development involving quantum entanglement and teleportation, via Richard Adhikari at TechNewsWorld

Scientists in China have transmitted quantum bits, or qubits, over a record distance of 97 km, or roughly 60 miles.

This is more than six times the distance of the previous record of 16 km, set by another team of Chinese researchers in May of 2010, as reported in Nature.com.

The results represent a step toward the establishment of a global quantum network, and the methods used in the experiment could be utilized for satellite-based quantum communications, the scientists said.

“This is just a transmission method, so it could have wide utility, though I expect the cost will initially make it best for huge data streams,” Rob Enderle, principal analyst at the Enderle Group, told TechNewsWorld.

This technology “could end up changing much of the world” because it’s both potentially higher bandwidth and lower latency, approaching zero, and these factors “could drive massive computer centralization on a world scale and force a massive shakeout of security , networking and computer companies,” Enderle continued. “Something like this could turn us into a SaaS (Software as a Service) world.”

This will change the satcom business in a big, big way. It’s right there in the abstract:

With the help of quantum entanglement, quantum communication can be achieved between arbitrarily distant places without passing through intermediate locations by quantum teleportation. In the laboratory, quantum teleportation has been demonstrated over short distance by photonic and atomic qubits. Using fiber links, quantum teleportation has been achieved over kilometer distances. Long distance quantum teleportation is of particular interest and has been one of the holy grails of practical quantum communication. Most recently, quantum teleportation over 16 km free-space link was demonstrated. However, a major restriction in this experiment is that the unknown quantum state cannot directly come from outside. Here, based on an ultra-bright multi-photon entanglement source, we demonstrate quantum teleportation, closely following the original scheme, for any unknown state created outside, between two optical free-space links separated by 97 km. Over a 35-53 dB high-loss quantum channel, an average fidelity of 80.4(9) % is achieved for six distinct initial states. Besides being of fundamental interest, our result represents an important step towards a global quantum network. Moreover, the high-frequency and high-accuracy acquiring, pointing and tracking (APT) technique developed in our experiment can be directly utilized for future satellite-based quantum communication.

Download the report (PDF) for yourself and read on.

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